IP_MAX_MEMBERSHIPS max value

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

Hello,
on a cups server with more than 20 interfaces avahi did hit the
IP_MAX_MEMBERSHIPS limit:
Feb 19 09:32:25 cups avahi-daemon[6948]: IP_ADD_MEMBERSHIP failed: Too many references: can't splice

In src/sys/netinet/in.h we have this:
#define        IP_MAX_MEMBERSHIPS      20      /* per socket; must fit in one mbuf */

but I failed to see where this value is used to size something that has
to fit in a socket. AFAIK the only place where this is used as a size is
in ip_var.h, for struct ip_moptions; wich is itself used in struct ip_pktopts.
But none of theses seems to be copied to the data part of an mbuf.

Did I miss something, or is this comment obsolete ?
I bumped it to 40 and didn't see any bad effects (others than mdns
now working on all interfaces :)

-- 
Manuel Bouyer <bouyer%antioche.eu.org@localhost>
     NetBSD: 26 ans d'experience feront toujours la difference
--